ES3024484T3 - Method and system of manufacturing a wind turbine blade - Google Patents

Abstract

A wind turbine blade includes a shell structure defining a leading edge and a trailing edge, and an upwind shell and a leeward shell joined along at least one of the leading and trailing edges. The shell structure includes a set of preformed pieces processed to form a prefabricated laminate assembly. The invention also includes a method of manufacturing wind turbine blades. This method includes processing several preformed pieces to form a prefabricated laminate assembly and assembling these laminates to construct a shell structure defining a leading edge and a trailing edge. (Automatic translation with Google Translate, no legal value)

Description

DESCRIPTION

Manufacturing process and system for a wind turbine blade

[0001]The present invention relates generally to wind turbines and more specifically to wind turbine rotors or blades typically reaching lengths of 50 meters and more. However, it is readily applicable to other types of wind-exposed surfaces or airfoils operating under aerodynamic forces, drag, and aerodynamics, such as helicopter rotor blades or fan blades.

Background

[0002]Modern wind turbines typically include a rotor with a considerable diameter size, as illustrated in FIG. 1. Referring to FIG. 1, a wind turbine 1 is typically mounted on a tower 2 and includes a wind turbine nacelle 3 located on top of the tower. The wind turbine rotor, which includes three wind turbine blades 5, is connected to the nacelle 3 via the slow shaft, which extends outwardly from the front of the nacelle. As illustrated in FIG. 1, wind beyond a certain level will activate the rotor due to the lift induced on the blades and allow it to rotate in a direction perpendicular to the wind. The rotational motion is converted into electrical power, which is typically supplied to the transmission grid as is known to those skilled in the art.

[0003]Wind turbine blades for modern wind turbine blades typically reach lengths of 50 meters or more. Large three-bladed wind turbine blades typically rotate with tip speeds in the range of 75 to 100 meters per second. For some two-bladed turbines, the blades can rotate with a tip speed as high as 130 meters per second. This causes very severe aerodynamic conditions at the blade tip, as well as along the outer A of the leading edge, resulting in blade stall in these areas. Although wind blades are typically expected to persist for 20 years, this is often not the case due to stall caused by aerodynamic conditions at the leading edge, which necessitate blade repair. However, leading edge repair is not easy, since it is typically carried out with the blade still upright on the turbine. This also has significant cost and safety implications, particularly if the wind turbine is located offshore.

[0004]To create wind turbine blades that can withstand significant wind forces as well as their own weight, the blades are constructed of two fiberglass shells and one or more internal load-bearing fiberglass beams, ribs, etc., all bonded together.

[0005]Current wind turbine blades are typically manufactured by laying rolls of fabric into large mould halves to build up the blade laminate layer by layer in the mould, see e.g. WO 2014/094787 A1. This conventional process has a number of shortcomings, namely it is slow and time consuming in the mould which is the restriction of the process, also there is a high risk of lamination defects such as wrinkles when laying down the fabrics in such a way. The problems worsen as the blades get larger since a larger proportion of the blade cycle time is used to lay the fabric in the mould. A further problem is that it is very difficult to automate and reduce the labour content of the blade manufacturing process due to the large and constantly changing scale of the blades.

[0006]Efforts have been made to try to automate the conventional procedure, but the constantly evolving scale of wind blades caused much of the investment to be lost when changing products and, in addition, the sheer size of the entire component makes the investment very high.

[0007]There is still scope to improve automation and reduce labor content in the manufacturing of wind turbine rotors or blades.

Declarations of invention

[0008]According to one aspect of the invention, there is provided a wind turbine blade including a shell structure defining a leading edge and a trailing edge, and an upwind shell and a downwind shell joined along at least one of the leading edge or the trailing edge. The shell structure includes an array of preformed parts processed into a collection of prefabricated laminates.

[0009]According to the invention, the shell structure includes a spar cap laminate manufactured from a first plurality of spar cap preforms, a root laminate manufactured from a second plurality of blade root preforms, and an aerodynamic fairing laminate manufactured from a third plurality of aerodynamic fairing preforms. Preferably, each of the first plurality of spar cap preforms, the second plurality of blade root preforms, and the third plurality of aerodynamic fairing preforms has a mass of less than 100 kg.

[0010]In another preferred embodiment, each of the first plurality of spar cover preformed pieces, the second plurality of blade root preformed pieces and the third plurality of aerodynamic fairing preformed pieces has a length of less than 7.5 m.

[0011]In another preferred embodiment, each of the first plurality of spar cap preforms, the second plurality of blade root preforms, and the third plurality of aerodynamic fairing preforms is created flat and is configured to assume a shape of the blade when assembled in plurality.

[0012]In yet another preferred embodiment, more than 60% of the first plurality of spar cover preforms, more than 60% of the second plurality of blade root preforms and more than 60% of the third plurality of aerodynamic fairing preforms are identical.

[0013]In another preferred embodiment, each of the first plurality of spar cover preforms, the second plurality of blade root preforms, and the third plurality of aerodynamic fairing preforms includes one or more of: thermosetting or thermoplastic resin, and furthermore, each of the plurality of preforms includes one or more of: no fiber, short fiber, or continuous fiber.

[0014]In another preferred embodiment, each of the first plurality of preformed pieces of spar cap laminate comprises predominantly more than 70% unidirectional (UD) fiber. Advantageously, each of the first plurality of preformed pieces of spar cap laminate has tapered ends.

[0015]In another preferred embodiment, each of the second plurality of root laminate preforms comprises a mixture of UD fiber and /-45 fiber. Advantageously, each of the second plurality of root laminate preforms has tapered ends.

[0016]In yet another preferred embodiment, each of the third plurality of aerodynamic fairing preforms comprises predominantly /-45 fiber and a core. Advantageously, each of the third plurality of aerodynamic fairing preforms comprises a plurality of fabric layers and a core layer.

[0017]In yet another preferred embodiment, the first plurality of spar cover preforms, the second plurality of blade root preforms and the third plurality of aerodynamic fairing preforms comprise preforms that are not blade specific and that can also be used to manufacture multiple products.

[0018]In a more preferred embodiment, the shell structure includes at least one shear web structure enclosed within, internally coupled to the shell structure and configured to provide structural integrity to the shell structure.

[0019]According to a second aspect of the present invention, there is provided a method of manufacturing a wind turbine blade. The method includes processing a plurality of preformed pieces into a collection of prefabricated laminates and assembling the collection of prefabricated laminates to construct a shell structure defining a leading edge and a trailing edge.

[0020]In accordance with the invention, assembling the prefabricated laminate collection includes assembling a first plurality of spar cap preforms to construct a first plurality of spar cap laminates, assembling a second plurality of blade root preforms to construct a second plurality of blade root laminates, assembling a third plurality of aerodynamic fairing preforms to construct a third plurality of aerodynamic fairing laminates, assembling said first plurality of spar cap laminates, said second plurality of blade root laminates and said third plurality of aerodynamic fairing laminates to construct said upwind shell and said leeward shell. Preferably, each of the first plurality of spar cover preforms, the second plurality of blade root preforms and the third plurality of aerodynamic fairing preforms has a mass of less than 100 kg.

[0021]In another preferred embodiment, each of the first plurality of spar cover preformed pieces, the second plurality of blade root preformed pieces and the third plurality of aerodynamic fairing preformed pieces has a length of less than 7.5 m.

[0022]In another preferred embodiment, each of the first plurality of spar cap preforms, the second plurality of blade root preforms, and the third plurality of aerodynamic fairing preforms is created flat and is configured to assume a shape of the blade when assembled in plurality.

[0023] In yet another preferred embodiment, more than 60% of the first plurality of spar cover preforms, more than 60% of the second plurality of blade root preforms and more than 60% of the third plurality of aerodynamic fairing preforms are identical.

[0024] In another preferred embodiment, each of the first plurality of spar cover preforms, the second plurality of blade root preforms, and the third plurality of aerodynamic fairing preforms includes one or more of: thermosetting or thermoplastic resin, and furthermore, each of the plurality of preforms includes one or more of: no fiber, short fiber, or continuous fiber.

[0025] In another preferred embodiment, each of the first plurality of preformed pieces of spar cap laminate predominantly comprises more than 70% unidirectional (UD) fiber. Advantageously, each of the first plurality of preformed pieces of spar cap laminate has tapered ends.

[0026] In another preferred embodiment, each of the second plurality of root laminate preforms comprises a mixture of UD fiber and /-45 fiber. Advantageously, each of the second plurality of root laminate preforms has tapered ends.

[0027] In yet another preferred embodiment, each of the third plurality of aerodynamic fairing preforms comprises predominantly /-45 fiber and a core. Advantageously, each of the third plurality of aerodynamic fairing preforms comprises a plurality of fabric layers and a core layer.

[0028] In yet another preferred embodiment, the first plurality of spar cap preforms, the second plurality of blade root preforms and the third plurality of aerodynamic fairing preforms comprise preforms that are not blade specific and that can also be used to manufacture multiple products.

[0029] In a more preferred embodiment, the method includes providing structural integrity to said shell structure by internally coupling and enclosing at least one web structure within said shell structure.

[0030] Various other features will become apparent from the following detailed description and drawings.

Brief description of the drawings

[0031] An example of the present invention will now be described with reference to the following drawings, in which:

FIG. 1 illustrates a large modern wind turbine,

FIG. 2 illustrates a cross-sectional view of the wind turbine blade of FIG. 1,

FIG. 3 illustrates a perspective view of the wind turbine blade of FIGS. 1 -2,

FIG. 4 illustrates a cross-sectional view of the root region of the wind turbine blade of FIGS.

1-3,

FIG. 5 illustrates a cross-sectional view of the root laminate and root region of the wind turbine blade of FIGS. 1-3,

FIG. 6 illustrates an alternative cross-sectional view of the root laminate and root region of the wind turbine blade of FIGS. 1-3,

FIG. 7 is a cross-sectional view of an aerodynamic fairing of the wind turbine blade of FIGS. 1-3,

FIG. 8 is a side and cross-sectional view of the main laminate of the wind turbine blade of FIGS. 1-3,

FIG. 9 is a cross-sectional view of the spar cap laminate, the root laminate, and the aerodynamic fairing laminate according to one embodiment of the wind turbine blade of FIGS. 1-3,

FIG. 10 is a cross-sectional view of the spar cap laminate, the root laminate, and the aerodynamic fairing laminate according to an alternative embodiment of the wind turbine blade of FIGS. 1-3, and

FIG. 11 illustrates a flow diagram of the manufacture of a wind turbine blade including a preferred embodiment of a preformed part according to the invention.

Detailed description

[0032] The present invention includes embodiments that relate to wind turbines and more specifically to wind turbine rotors or blades. However, it is readily applicable to other types of wind-exposed airfoil surfaces that operate under aerodynamic forces, drag, and aerodynamics, such as helicopter rotor blades or fan blades.

[0033] One skilled in the art will recognize that it is possible to manufacture wind turbine blade sections from one or more very small, easily controllable and constructible preformed pieces. The pieces are of a size that they no longer require large cranes to move them, and can therefore be moved around and placed into the mold by much faster and more agile means than large cranes.

[0034] The parts are also designed so that they can be 'preformed' outside the main blade mold (preforming refers to the depositing of a series of layers on each part).

[0035] This helps in many ways. First, there is less likelihood of defects such as wrinkles, as the basic components are smaller and more controllable. Second, the relatively smaller size of typical preformed parts means that the blade manufacturing process can be more easily automated, thereby reducing labor and also increasing quality and deposition rates. Third, it opens up the possibility of preforming flat materials, which means they can be transported efficiently. This means they could be preformed at another location and time and transported cost-effectively to the final blade factory. Finally, the preforming process allows a number of more cost-effective types of materials to be used that are cheaper and more structurally effective.

[0036] Preformed parts typically consist of 2-10 layers of fabric that taper at the ends and may be held together by adhesive, stitching, or rivets. A significant number of identical preformed parts may be used in the upper. This helps to reduce costs by driving standardization.

[0037] In operation, the preformed pieces are then collected, transported to the blade mold, and then placed in the blade mold with the appropriate accuracy. As the pieces are placed in the mold, they change shape and adapt to the local shape of the mold. In another embodiment of the invention, wherein the spar cap preformed pieces, the blade root preformed pieces, and the aerodynamic fairing preformed pieces are not blade specific and can further be used to manufacture multiple different blade parts, products, or components.

[0038] In one embodiment of the invention, each of the plurality of preformed pieces has a mass of less than 200 kg and preferably less than 100 kg. In another embodiment of the invention, each of the plurality of preformed pieces has a length of less than 12 m and preferably a length of less than 7.5 m, so that the preform pieces can fit into a shipping container.

[0039] In yet another embodiment of the invention, each of the plurality of preformed pieces is created flat and is configured to assume a shape of the blade when assembled in a plurality. In another embodiment of the invention, each of the plurality of preformed pieces that form the spar cap laminate has tapered ends.

[0040] In one embodiment of the invention, more than 50% and more preferably 60% of the plurality of preforms of each type, in other words, spar cover laminate preforms, root laminate preforms and aerodynamic fairing laminate preforms, are identical. In another embodiment of the invention, each of the plurality of preforms forming the spar cover laminate predominantly comprises less than 70% and preferably less than 90% unidirectional (UD) fiber. In another embodiment of the invention, each of the plurality of preforms forming the root laminate comprises 60% UD fiber and 40% /-45 fiber.

[0041] In one embodiment of the invention, each of the plurality of preformed pieces comprises thermosetting or thermoplastic resin and further wherein each of the plurality of preformed pieces comprises no fiber, short fiber or continuous fiber.

[0042] In another embodiment of the invention, each of the plurality of preformed pieces forming the aerodynamic fairing comprises predominantly /-45 fiber and a core. In yet another embodiment of the invention, each of the plurality of preformed pieces forming the aerodynamic fairing comprises a plurality of fabric layers and a core layer.

[0043] FIG. 2 illustrates a cross-sectional view 20 of the wind turbine blade 5 of FIG. 1. The blade 5 includes a leeward shell 12 and a windward shell 14 joined along a first longitudinal edge (leading edge) 18 and a second longitudinal edge (trailing edge) 22 to constitute a complete and closed shell structure 11. A typical web structure 16 including flanges is enclosed within and internally coupled to the shell structure. The web structure 16 supports and provides structural integrity to the shell structure 11.

[0044] FIG. 3 illustrates a perspective view of the wind turbine blade of FIGS. 1-2. Referring to FIG. 3, first and second spar cap laminates 34 and 35 are secured to blade segment 32. The first and second spar cap laminates 34 and 35 are configured to form an exemplary joint, such as a scarf joint. Blade segment 32 is a hollow segment comprising an outer skin 36. The skin is fabricated from materials that are lightweight and strong. The spar caps 34 carry longitudinal loads experienced by the wind turbine blades and are secured to the interior of the skin of the blade segments. Wind turbine blade 10 also includes a bulkhead 38 at the intersection of the blade segments. The bulkhead 38 further increases the structural strength of the wind turbine blade. The spar cap laminates 34 and 35 typically include a material, such as carbon or fiberglass composites, that is strong and can withstand longitudinal loads.

[0045]Referring to FIGS. 1, 2 and 3, the partition wall 38 is at the connection between the outer skins of the first and second blade segments. A first bulkhead flange portion is bonded to the inner surface of the blade segment outer skin 32. The bulkhead 38 includes a leading edge bulkhead and a trailing edge bulkhead separated by a gap to accommodate a web 39 (16 in FIG. 2) for connecting the spar cap 34. The bulkhead central portion is represented by the sides of the leading edge bulkhead and the trailing edge bulkhead facing each other and is configured to accommodate the spar cap laminates 34 and 35 by including recesses sized to receive the spar cap laminates 34 and 35. The bulkhead typically comprises materials, such as carbon or fiberglass composites. The thickness of the bulkhead is typically 5-10 mm.

[0046]As shown in the embodiment of FIGS. 1, 2, and 3, the spar cap laminates 34 and 35 include tapered and non-tapered sections, and a distance between the two tapered sections remains substantially constant along the length of the tapered sections. As used herein, substantially constant typically means plus or minus 25 percent of the average gap. The web 39 of the spar cap laminates 34 and 35 connects the non-tapered sections of the first spar cap 34. The second spar cap 35 also includes tapered and non-tapered sections. Alignment occurs over the tapered sections of the first and second spar cap segments. Specifically, the outer sides of the tapered sections of the first spar cap 34 are straight, while the inner sides are tapered to the end. The inner sides of the tapered sections of the second spar cap 35 are straight, while the outer sides are tapered to the end. To form the alignment, the tapered inner sides of the first spar cap segments are positioned over the tapered outer sides of the second spar cap segments. This typically forms a bevel joint, as a non-limiting example. In another example, the length of the tapered section is 20 to 80 times greater than the thickness of the untapered section for both the first and second spar cap segments.

[0047]Referring to FIGS. 2 and 3, in one embodiment of the invention, the preformed parts are joined together with joining elements to form the wind turbine shell structure. In one embodiment of the invention, the joining elements or the adhesive means are a one- or two-component adhesive, such as epoxy, polyurethane or methacrylate adhesives, and it is possible to create a particularly durable bond in relation to the different kinds of climatic conditions to which a wind turbine blade is exposed.

[0048]The different preformed pieces are typically adapted to the section of the wind turbine blade they cover. In particular, the widths of the preformed pieces vary to satisfy the different dimensions of the wind turbine blade at different positions, for example, the width at the root compared to the width at the tip. The height of the preformed pieces, and thus the side-to-side length of the preformed pieces, may also vary to satisfy the aforementioned different dimensions of the wind turbine blade.

[0049]In a preferred embodiment, a preform preferably includes a width and a height ranging from 0.02 to 0.2 meters wide and from 0.05 to 0.2 meters high, corresponding to the shape of different parts of the wind turbine blade and has a thickness range from 0.1 to 5 mm, preferably from 0.5 to 1.5 mm, for example 0.5 mm, at or near the ends of the edge sections and 3 mm in the center of the preform. Furthermore, advantageously, the ends may be rounded to establish a smoother crossing with respect to the wind turbine blade and, in a preferred embodiment, the adhesive layer is from 10 to 100 mm, such as 50 mm.

[0050] Referring to FIGS. 2, 3 and 4, the web structures 16 typically include spar cap laminates mutually connected by two plates. The wind turbine blade beam and shells may be fabricated from glass fiber reinforced plastic (GRP), i.e., epoxy or glass fiber reinforced polyester. However, other reinforcement materials may be used, such as carbon fiber or aramid (Kevlar). Wood, wood-epoxy, wood-fiber-epoxy, or similar composite materials may also be used as wind turbine blade materials.

[0051] In a preferred embodiment, a preform may typically be manufactured from a variety of materials or combinations of materials by various production methods. For example, in a preferred embodiment, the preform is manufactured from plastic by an injection molding machine. In another embodiment, casting in a mold is used to create the preform from fiberglass material or a similar fiber material, such as carbon fiber or aramid material, reinforcing an epoxy or polyester resin. Furthermore, the preform may be manufactured from a thin metal plate, for example, a sheet metal with the distance means welded or bonded to the plate. The metals are preferably chosen from lighter metals, such as aluminum. The preform may also be manufactured from different materials, such as a plastic plate with rubber distance means.

[0052] FIG. 4 illustrates a cross-sectional view 40 of the root region of the wind turbine blade of FIGS. 1-3. FIG. 5 illustrates a cross-sectional view 50 of the root laminate 52 and the root region of the wind turbine blade of FIGS. 1-3. FIG. 6 illustrates an alternative cross-sectional view 60 of the root laminate 52 and the root region of the wind turbine blade of FIGS. 1-3.

[0053] Most modern wind turbine blades are made of fiberglass-reinforced plastic or carbon. As is known in the art, the root (hub) end of the blade is typically made of fiberglass combined with epoxy resin (and sometimes from the polyester, vinyl ester, and polyurethane resin families). Typical manufacturing processes are prepreg or vacuum-infused resin processes.

[0054] The thickness of the laminate 52 required at the root end can be very high compared to other parts of the wind turbine blade and is often in the range of 50 mm-80 mm thick, but with more modern blades it can be up to 150 mm thick. This high thickness can lead to manufacturing problems. As the resin system cures, it generates heat in an exothermic reaction. In the thickened areas of the root, the heat generated can be so high as to cause damage to the finished component, rendering it unusable.

[0055] A typical root end forming procedure is shown in FIGS. 4, 5 and 6. In this case, the dried fabric matrix is placed in the mold of a suitable shape. The resin is then infused and cured into the finished part as shown in FIG. 4. Once the root component of the blade is cured, it is typically transferred to a drilling location where a series of holes 4 are drilled into the end of the root laminate to allow female threaded metal root insert members to be joined or mechanically fixed in place. Two semi-circular sub-assemblies are then joined to form the finished root end joint as shown in FIG. 4.

[0056] As illustrated in the figures, the first preformed piece 52 may start at the root of the wind turbine blade and the last preformed piece may end at the tip of the blade, creating a continuous line of preformed pieces, each covering a section of the blade. However, the preformed pieces may also start and end at other positions, for example, start and end some distance from the root and the tip.

[0057] Furthermore, one or more preformed pieces may cover different sections of the wind turbine blade, for example, a section at the center and the blade root with an uncovered section in between or simply one preformed piece covering a section of the blade. The preformed pieces are preferably adapted to form an aerodynamic profile with the wind turbine blade in relation to the wind.

[0058] A series of segments are used as shown in FIGS. 4, 5 and 6 to construct a root end joint for a wind turbine. Each of the segments has a connecting end in which a plurality of holes are formed and an opposite end. The segment has the general shape of a segment of a hollow cylinder that tapers in thickness from the connecting end to the opposite end. Generally, it is intended that 16 segments (8 in each half) will be connected together to form the complete root end. In this case, each segment will subtend an angle of 22.5° at the center of the hub.

[0059] However, there may be as few as 4 such segments (2 in each half) subtending a 90° angle, or more than 16 segments for larger blades subtending a correspondingly smaller angle. On each side of the segment, there is typically a key 14, 15 designed to locate and interlock with a corresponding key in an adjacent segment.

[0060]Typically, each segment will be 2000 mm long and 500 mm wide. At the connecting end, there is a significant amount of unidirectional fiber with a small percentage of biaxial fiber. The amount of fiber moves to the opposite end 13 where it ends up being 1 ply thick. Depending on its application (infused blade root or prepreg), the root segment is manufactured in one of two ways.

[0061]For an infused blade, it can be manufactured by wet vacuum lamination, vacuum resin infusion, resin transfer molding or a similar process. The first layers of the fiber are placed in the tool, then tubular spacers or metal insert members are placed in the tool and held in position with an alignment frame at the end of the tool. The alignment frame allows exact positioning of the insert members. The final layers of fiber are then placed in the tool. The entire lamination is then placed under vacuum and the resin is either infused or injected and then fully cured.

[0062]For a prepreg blade, the procedure is very similar, except that prepreg layers are inserted into the tool instead of fiber layers. The prepreg lamination is then vacuum-sealed and partially cured so that it becomes a semi-cured preform.

[0063] Alternatively, the segments may be manufactured without the insert members or spacers 16 and the holes are drilled at a later stage in a separate jig. Once the individual root segments are manufactured, they may be subjected to a quality control procedure to assess the structural integrity of the segments and also to assess the integrity of the insert members. The insert members may be conventional metal insert members that are well known in the art. Alternatively, they may be the insert members disclosed in earlier WO 2010/041008.

[0064]The root end joint assembly is shown in FIGS. 4, 5 and 6. In FIG. 4, four segments are shown to form one half of the root end joint. In practice, there will typically be eight. The segments are placed in a tool having a generally semi-circular configuration before any other laminate is placed in the tool. The root end of the insert member is connected to an alignment frame and bolted in place using bolts 16. This ensures that the bolt circle alignment is maintained during the manufacturing process. In step b), once the segments are accurately positioned, the remainder of the blade laminate is laid. The laminate effectively forms a very long bevel joint with the laminate tapering at the root segment. Once all the laminate has been laid, the blade is placed under vacuum and either infused with resin (if an infusion blade) or simply cured (if a prepreg blade). The blade half is then complete and ready for final assembly of the two blade halves in the normal manner.

[0065] FIG. 7 is a cross-sectional view 70 of an aerodynamic fairing of the wind turbine blade of FIGS. 1-3. Referring to FIG. 7, the aerodynamic fairing laminate 72 is shown. The aerodynamic fairing laminate 72 is formed from a fairing 74 and a preform 76 attached to an outer surface 78 of the fairing 74 at the leading edge 79 of the fairing laminate 72.

[0066]Referring to FIG. 7, the preform 76 comprises an outer layer of thermoplastic film fused to a fiber substrate. The thermoplastic film is formed from an aliphatic polyurethane, which is approximately 600 micrometers thick and can be produced using long and short chain polyether, polyester, or caprolactone glycols. The polyether types have better hydrolytic stability and low temperature flexibility, the polyester types have better mechanical properties, and the caprolactones offer a good balance between the properties of the polyether and polyester types. In this example, caprolactone glycols are used. This results in the film having a Shore A hardness of approximately 75 to 95, an elongation of at least 300%, and a surface energy in the region of 40 to 44 mN/m. The fiber substrate is a glass fiber cloth preform that is multiaxial and has a weight of approximately 150 g/m2.

[0067]In operation, the preform 76 is placed in a mold with the thermoplastic film against the mold surface. Following this, 76 layers of prepreg, which are formed from glass or carbon fibers preimpregnated with an epoxy resin, are placed over the preform to form the typical composite laminate required for a fairing.

[0068]The preform 76 and the prepreg layers are then cured together under vacuum and at a temperature between 60 and 130°C for approximately 12 hours in the same manner as for normal prepreg processing. As the stack of layer 74 and prepreg layers cures, the resin in the prepreg migrates to and impregnates the fiber substrate. The resin is then fully cured to form the fairing 74 from the prepreg and to affix the preform 76 to the composite body 74. In doing so, the resin forms a continuous matrix through the composite body 74 and the preform 76 to firmly bond the two layers together. The resin also forms a chemical bond with the thermoplastic film, further strengthening the attachment of the preform 76 to the composite body 74. In this way, the resulting point of contact between the fairing 74 and the preform 76 is well controlled and the fairing 74 and the fiber substrate provide a very high quality substrate directly beneath the thermoplastic film.

[0069]As the fairing 74 and preform 76 are cured together, the fairing 74 is formed around the preform 76 such that the edges of the preform 76 are flush with the fairing 74. This gives the resulting fairing laminate 72 a smooth exterior profile, as shown in FIG. 7. This smooth profile reduces the impact of the preform 76 on aerodynamic performance and prevents the presentation of free edges that might otherwise cause the preform 76 to be more easily removed from the fairing 74.

[0070] FIG. 8 is a side and cross-sectional view of the main laminate of the wind turbine blade of FIGS. 1-3. FIG. 9 is a cross-sectional view of the spar cap laminates 34 and 35 (FIG.

3), of the root laminate 52 (FIG. 5) and of the aerodynamic fairing laminate 72 according to an embodiment of the wind turbine blade of FIGS. 1-3. FIG. 10 is a cross-sectional view of the spar cap laminates 34, 35, of the root laminate 52 and of the aerodynamic fairing laminate 72 according to an alternative embodiment of the wind turbine blade of FIGS. 1-7.

[0071]In one embodiment of the invention, the preform components may be constructed of a continuous, organic or inorganic fibrous material and impregnated with resin, such as epoxy, vinyl ester, polyester, or the like, as is known in the art. Referring to FIG. 9, the fibrous material of the preform component 92 may have a woven configuration and may be constructed, for example, from carbon, glass, synthetic material, or the like, as is known in the art. The preform component 92 may have a length shorter than the desired length of the spar cap laminates 34, 35, the root laminate 52, and the aerodynamic fairing laminate 72, and thus, multiple preform components 92 may be affixed together to form all of the spar cap laminates 34, 35, the root laminate 52, and the aerodynamic fairing laminate 72.

[0072]Each preform component 92 may typically have a swept contour so that when assembled together to form the spar cap laminates 34, 35, the root laminate 52 and the aerodynamic fairing laminate 72 will have the desired domed, or banana, shape following the shape of a domed rotor blade. It should also be appreciated that the preform component 92 may be substantially straight and may be used to assemble substantially straight spar cap laminates 34, 35, the root laminate 52 and the aerodynamic fairing laminate 72 in the same manner just described. The preform component 92 may have a first angled end forming an obtuse angle with the top side of the preform component 92. The preform component may have a second angled end, opposite the first angled end, forming an acute angle with the top side of the preform component 92. The second angled end may be formed at an angle complementary to the angle of the first angled end. In securing multiple preform components 92 together, the first angled end of a first preform component 92 may be aligned and fitted with the second angled end of a second preform component 92, forming a bevel joint.

[0073]In operation, multiple preform components may be attached to form the spar cap laminates 34, 35, the root laminate 52, and the aerodynamic fairing laminate 72. The first preform component 92, having the first angled end, may be mated with the second preform component 92, having the second angled end, placing an intermediate joint contact point layer between the two angled ends and creating an exemplary and non-limiting bevel joint. The joint contact point layer may be a polymeric material and may further include a fiber substrate, such as fiberglass or the like, as is known in the art. One or more pins may be inserted through the mated bevel joint. The pins may be constructed of a rigid material, such as a robust metal; however, the pins need not be metallic. Furthermore, the pins need not be cylindrical in shape, but may be of any shape that forms continuous contact across the bevel joint and the first and second preform components 92, such as a flat sheet, a grooved sheet, or the like. The pins further reinforce the bevel joint in the out-of-plane direction, while also maintaining alignment between adjacent preform components 92 as they form the entire spar cap laminates 34, 35, root laminate 52, and aerodynamic fairing laminate 72.

[0074]In another exemplary embodiment of the invention, multiple preform components may have one or more facing layers on at least one side of the spar cap laminates 34, 35, the root laminate 52, and the aerodynamic fairing laminate 72 and covering the miter joints. The facing layers may be a polymeric material and may further include a fiber substrate, such as fiberglass or the like, as is known in the art. The facing layers, like the pins, further reinforce the miter joint and maintain alignment between adjacent preform components 92. It is appreciated that while the facing layers are present on only one side of the spar cover laminates 34, 35, the root laminate 52 and the aerodynamic fairing laminate 72, the facing layers may be applied to either one or both sides of the spar cover laminates 34, 35, the root laminate 52 and the aerodynamic fairing laminate 72.

It is also contemplated that multiple preform components 92 may be joined in a side-by-side configuration as well as an end-to-end configuration. In this embodiment, the sides of each preform component 92 may have complementary acute and obtuse angles such that a bevel joint, as described above, may be formed between the side-by-side as well as end-to-end preform components 92.

[0075]In operation, an appropriate molding tool may be used to fabricate the spar cap laminates 34, 35, the root laminate 52, and the aerodynamic fairing laminate 72 from multiple preformed components 92. Because the preform components 92 may be flat when first received from the manufacturer, the molding tool may be used to form the preform components 92 into an arcuate, rather than flat, shape. The arcuate shape will follow the arc of the rotor blade from leading edge to trailing edge as shown in FIG. 2. The molding tool includes a convex shape with a surface having a convex curve that follows the arcuate shape of either the first shell or the second shell of the rotor blade. To form the spar cap laminates 34, 35, the root laminate 52, and the aerodynamic fairing laminate 72, multiple preform components 92 may be placed over the convex shape and aligned end-to-end.

[0076]The convex shape may also include one or more alignment fences that will communicate with one side of the preform components 92 when placed into the convex shape, further maintaining alignment of the adjacent preform components 92. In an exemplary embodiment, one or a plurality of alignment fences are positioned on each side of the convex shape and opposite each other to hold the preform components 92 in place. Finally, the alignment fence may include alignment marks along the length of the fence to identify where to align each of the preform components 92. In one embodiment of the present invention, two different molding tools may be employed, whereby a first molding tool includes the convex mold shape having the shape of the first shell forming the upper rotor blade skin, and whereby a second molding tool includes the convex mold shape having the shape of the second shell forming the lower rotor blade skin.

[0077]After final construction and integration with the rotor blade, the spar cap laminates 34, 35, the root laminate 52, and the aerodynamic fairing laminate 72 may include multiple preform components 92 placed end-to-end and secured by the miter joint. It should be appreciated that the width of the multiple preform components 92 may not be the same, allowing the spar cap laminates 34, 35, the root laminate 52, and the aerodynamic fairing laminate 72 to taper at one or both ends and remain wider in the intermediate sections. Furthermore, the thickness of the multiple preform components 92 may not be the same, allowing the spar cap laminates 34, 35, root laminate 52, and aerodynamic fairing laminate 72 to taper in thickness at one or both ends and remain thicker in the intervening sections. It should be further appreciated that any number of preform components 92 may be used to achieve the necessary length and desired domed contour, considering the size and availability of the preform components 92. Additionally, while FIGS. 8-10 show the spar cap laminates 34, 35, the root laminate 52 and the aerodynamic fairing laminate 72 in a domed shape, it should be appreciated that spar cap laminates 34, 35, the root laminate 52 and the aerodynamic fairing laminate 72 can be formed in a generally straight shape from multiple preform components 92 that do not have a curved shape.

[0078]It should be apparent that the foregoing relates only to exemplary embodiments of the present application and that numerous changes and modifications may be made therein by one skilled in the art without departing from the general spirit and scope of the invention as defined by the following claims and equivalents thereof.

[0079] FIG. 11 illustrates a flow diagram of a method 150 for manufacturing a wind turbine blade including a preferred embodiment of a preform according to the invention. The manufacturing method 150 includes the steps of: joining (152) at least one upwind shell and at least one downwind shell along a first longitudinal edge and a second longitudinal edge to form a shell structure; manufacturing a spar cap laminate (154) from a plurality of preforms; manufacturing a root laminate (156) from a plurality of preforms; manufacturing an aerodynamic fairing laminate (158) from a plurality of preforms; assembling (162) the spar cap laminate, the root laminate, and the aerodynamic fairing laminate into the shell structure; and enclosing and internally coupling (164) the web structure.

[0080] A technical contribution to the disclosed method and apparatus is that it provides a wind turbine blade manufactured from a plurality of preformed pieces that can be manufactured at different locations at different times and assembled together. The technical contribution also includes a method of manufacturing the wind turbine blade from a plurality of preformed pieces that can be manufactured at different locations and at different times.

[0081]In accordance with one aspect of the present invention, there is provided a wind turbine blade including a shell structure defining a leading edge and a trailing edge, and an upwind shell and a leeward shell joined along at least one of the leading edge or the trailing edge. The shell structure includes an array of preformed parts processed into a collection of prefabricated laminates.

[0082]According to a second aspect of the present invention, there is provided a method of manufacturing a wind turbine blade. The method includes processing a plurality of preformed pieces into a collection of prefabricated laminates and assembling the collection of prefabricated laminates to construct a shell structure defining a leading edge and a trailing edge.

List

[0083]

1. Wind turbine

2. Wind turbine tower

3. Wind turbine nacelle

4. Wind turbine hub

5. Wind turbine blade

20 wind turbine blade isometric view

11 shell structure

12 leeward shell

14 shell to windward

16 soul structure

24 soul

26 leading edge

28 trailing edge

30 perspective view of wind turbine blade

32 blade segment

34 first spar cover

35 second spar cover

36 lining

38 partition wall

39 soul

40 cross-sectional view of the root region

50 Alternative cross-sectional view of the root region

52 root laminate

60 Alternative cross-sectional view of the root region

70 cross-sectional view of an aerodynamic fairing

72 laminated aerodynamic fairing

74 fairing

76 preform

78 exterior surface

79 leading edge of fairing laminate 72

80 side and cross-sectional view of the main laminate

90 Cross-sectional view of the spar cover laminate, the root laminate and the aerodynamic fairing laminate

92 preformed part or component

100 Cross-sectional view of the spar cover laminate, the root laminate and the aerodynamic fairing laminate

150 Wind turbine blade manufacturing procedure

152 assemble preformed pieces to build a lamination of a stringer cap

154 assemble preformed pieces to build a root sandwich construction

156 Assemble preformed parts to build an aerodynamic fairing sandwich construction 158 Assemble a spar cap laminate, root laminate, and aerodynamic fairing laminate to construct a windward shell and a leeward shell

162 join the windward and leeward shells along the longitudinal edges to construct a shell structure

164 enclose and internally couple a soul structure

Claims (16)

1. A wind turbine blade (1) comprising: a shell structure (11) defining a leading edge (26) and a trailing edge (28); and an upwind shell (14) and a leeward shell (12) joined along at least one of: said leading edge or said trailing edge, wherein said shell structure comprises a root laminate (52) manufactured from a second plurality of blade root preforms, characterized in that the shell structure comprises: a spar cap laminate (34, 35) manufactured from a first plurality of preformed spar cap pieces, and an aerodynamic fairing laminate (72) manufactured from a third plurality of preformed aerodynamic fairing pieces. 2. The wind turbine blade according to claim 1, wherein each of said first plurality of spar cap preforms, said second plurality of blade root preforms and said third plurality of aerodynamic fairing preforms has a mass of less than 100 kg and wherein each of said first plurality of spar cap preforms, said second plurality of blade root preforms and said third plurality of aerodynamic fairing preforms has a length of less than 7.5 m. 3. The wind turbine blade according to claim 1, wherein each of said first plurality of spar cap preforms, said second plurality of blade root preforms, and said third plurality of aerodynamic fairing preforms is created flat and is configured to assume a shape of the blade when assembled in plurality. 4. The wind turbine blade according to claim 1, wherein more than 60% of said first plurality of spar cap preforms, more than 60% of said second plurality of blade root preforms, and more than 60% of said third plurality of aerodynamic fairing preforms are identical. 5. The wind turbine blade according to claim 1, wherein each of said first plurality of spar cap preforms, said second plurality of blade root preforms and said third plurality of aerodynamic fairing preforms comprises one or more of: thermosetting or thermoplastic resin and further wherein each of said plurality of preforms comprises one or more of: no fiber, short fiber or continuous fiber. 6. The wind turbine blade according to claim 1, wherein each of said first plurality of spar cap laminate preforms predominantly comprises more than 70% unidirectional (UD) fiber. 7. The wind turbine blade according to claim 1, wherein each of said second plurality of root laminate preforms comprises a mixture of UD fiber and /-45 fiber. 8. The wind turbine blade according to claim 1, wherein each of said third plurality of aerodynamic fairing preforms predominantly comprises /-45 fiber and a core. 9. A method (150) for manufacturing a wind turbine blade, said method comprising: processing a plurality of preformed pieces into a collection of prefabricated laminates; assembling said collection of prefabricated laminates to construct a shell structure defining a leading edge and a trailing edge, wherein said shell structure comprises a windward shell and a leeward shell joined along at least one of: said leading edge or said trailing edge, wherein said assembling said collection of prefabricated laminates comprises: assembling (152) a first plurality of preformed spar cap pieces to construct a first plurality of spar cap laminates; assembling (154) a second plurality of blade root preforms to construct a second plurality of blade root laminates; assembling (156) a third plurality of preformed aerodynamic fairing pieces to construct a third plurality of aerodynamic fairing laminates; assembling (158) said first plurality of spar cap laminates, said second plurality of blade root laminates and said third plurality of aerodynamic fairing laminates to construct said upwind shell and said leeward shell. 10. The method of claim 9, wherein each of said first plurality of spar cover preforms, said second plurality of blade root preforms and said third plurality of aerodynamic fairing preforms has a mass of less than 100 kg and wherein each of said first plurality of spar cover preforms, said second plurality of blade root preforms and said third plurality of aerodynamic fairing preforms has a length of less than 7.5 m. 11. The method of claim 9, wherein each of said first plurality of spar cap preforms, said second plurality of blade root preforms, and said third plurality of aerodynamic fairing preforms is created planar and is configured to assume a shape of the blade when assembled in plurality. 12. The method of claim 9, wherein more than 60% of said first plurality of spar cap preforms, more than 60% of said second plurality of blade root preforms, and more than 60% of said third plurality of aerodynamic fairing preforms are identical. 13. The method of claim 9, wherein each of said first plurality of spar cap preforms, said second plurality of blade root preforms, and said third plurality of aerodynamic fairing preforms comprises one or more of: thermosetting or thermoplastic resin, and further wherein each of said plurality of preforms comprises one or more of: no fiber, short fiber, or continuous fiber. 14. The method of claim 9, wherein each of said plurality of preformed pieces of spar cap laminate predominantly comprises more than 70% unidirectional (UD) fiber. 15. The method of claim 9, wherein each of said second plurality of preformed root laminate pieces comprises a mixture of UD fiber and /-45 fiber. 16. The method of claim 9, wherein each of said third plurality of aerodynamic fairing preforms predominantly comprises /-45 fiber and a core.